Process for delustring textile materials



l L I Unite PROCESS FOR DELUSTRING TEXTILE MATERIALS Peter Howard Haycock, Chorlton-cum-Hardy, and John James Ryan and Margaret 'inson, Manchester, England. assignors to Tootal Broadhnrst Lee Company Limited, Manchester, England, a British company No Drawing. Filed Apr. 30, 1956, Ser. No. 581,324

Claims priority, applicafion Great Britain Apr. 30, 1955 Claims. (Cl. 117-4395) This invention relates to a process for delustring textile materials.

The textile materials treated may be fibres, yarns or fabrics of natural or artificial origin, including natural silk and artificial silk of all types, e.g. cellulose others or esters or regenerated cellulose such as viscose rayon.

A simplified flow diagram of the process of the invention is as follows:

impregnate with solution Impregnate with solution of acid salt of Polybasic of metal salt of acid stronger than subseacid.

quent polybasic acid.

Imoregnate with solutio Impregnate with solution of metal salt of acid of acid salt of polybasic stronger than above acid. polybasic acid.

Dry

Heat to temperature of about 100 C.

It is known that fabrics and other textile materials can be weighted and/or delustred by precipitating an insoluble non-resinous condensation product in the form of finely divided particles from urea or urea-like substances and formaldehyde or from soluble partial condensates thereof used for impregnating the material, by the addition of an acid or a substance liberating an acid before, during or after impregnation so that the precipitate is formed directly on the textile material. The precipitant used in that process is preferably an acid and the textile material may be impregnated with any two of the three components of the reaction and then treated with the third or may be impregnated with any one of the three components and then treated with the other two.

The insoluble condensation products of urea and formaldehyde, in the form of white, amorphous discrete particles, known as methylene ureas are excellent delustrants and are capable of being formed by precipitation at ordinary temperature. If heat is used at all in their preparation, it is necessary carefully to avoid either an unduly high temperature or an excessive time of heating, otherwise synthetic resin formation will take place. Although the precipitant is an acid, the urea-formaldehyde mixture may contain a potential precipitant (i.e. one capable of liberating the acid precipitant under the conditions of treatment) e.g. the ammonium salt of an acid, which acid States Patent 0 will then be liberated on warming or treating the impregnated material with wet steam, provided that resin-formation is avoided.

We have now discovered an improved method by which acid may be liberated in an aqueous solution containing the ingredients of an amino-aldehyde condensation product whereby a condensation product is precipitated in particulate form, suitable for effecting delustring of textile materials.

As pointed out in our application Serial No. 581,508, filed April 30, 1956, when an aqueous solution of sodium dihydrogen phosphate is concentrated by evaporation at room temperature, i.e. substantially 20 C., the salt which first separates out is sodium dihydrogen phosphate. On the other hand, when an aqueous solution of magnesium dihydrogen phosphate is concentrated by evaporation at room temperature, the salt which first separates out is magnesium monohydrogen phosphate. During the removal of solvent by evaporation, the pH of both these solutions falls; but in the case of the solution of magnesium dihydrogen phosphate, the eifect of the separation of magnesium monohydrogen phosphate is that the rate of increase of acidity with increase in the proportion of magnesium in solution becomes greater after the point is reached at which the separation begins.

The term phosphoric acid is used herein to mean orthophosphoric acid and the term phosphate to mean orthophosphate.

We have found that this effect can also be realised with acid salts of polybasic acids, other than magnesium dihydrogen phosphate. Solutions of acid salts from which a less acid salt will separate before such acid salt on removal of solvent can be obtained from polybasic acids other than phosphoric acid, for example phosphorous acid, pyrophosphoric acid, malonic acid, oxalic acid, maleic acid, tartaric and phthalic acid. Examples of metals, other than magnesium, are given hereinafter. It is simply necessary that the acid salt be that of a metal or cation of which a less acid salt with the same polybasic acid is precipitated before said acid salt on mere removal of solvent from the solution. Such metal or cation will hereinafter be referred to as a selected metal.

By the term acid salt We mean a salt in which less than all of the replaceable hydrogen atoms in the polybasic acid molecule are replaced by the selected metal and the other replaceable hydrogen atom'or atoms is or are unreplaced.

By the term less acid salt we mean a salt in which more of the replaceable hydrogen atoms in the polybasic acid molecules are replaced by the selected metal than in the case of said acid salt; the term includes salts in which all of the replaceable hydrogen atoms are so replaced.

As further pointed out in the said application Serial No. 581,508, April 30, 1956, these effects can be brought about in solutions containing the ingredients of aminoaldehyde condensation products. It thus becomes possible to make aqueous solutions, containing the ingreclients of such condensation products, which, on removal of solvent, will show a rapid fall in pH after a critical concentration has been reached, thereby enabling the acid-catalysed condensation to take place. In order that such condensation be effectively acid-catalysed, it is necessary that the polybasic acid be one having a first dissociation constant in water of not less than 10- The critical concentration referred to above is the concentration at which the solution becomes saturated with respect to the less acid salt which separates out before the acid salt. The critical concentration depends upon the nature of the selected metal, upon the nature of the polybasic acid and upon the ionizing solvent em! ployed and may be altered by other ingredients in the solution, especially any common ions. However, it is generally possible to determine the critical concentration for any solution by making pH measurements at various concentrations and at the temperature at which it is desired to use the system and drawing a graph showing the relationship between pH and concentration. The slope of the curve alters suddenly at the point where the less acid salt of the selected metal begins to separate out. The word concentration refers to the concentration of the selected metal in solution. Several such graphs are described in the said application Serial No. 581,508, filed April 30, 1956.

According to one embodiment of the process of that application there is provided a solution in an ionizing solvent such as water of the ingredients of an aminoaldehyde condensation product whose formation is catalysed by acid, containing in solution an acid salt of a polybasic acid having a first dissociation constant in water of not less than with a metal of which a less acid salt with the same polybasic acid is precipitated before said acid salt on removal of solvent from the solution. Preferably the solution contains a dihydrogen phosphate of a metal whose trimetal phosphate or mono hydrogen phosphate will separate before its dihydrogen phosphate on removal of solvent from the solution, such as magnesium dihydrogen phosphate.

A very convenient way of producing an aqueous solution containing the dihydrogen phosphate of such a metal is to introduce into an aqueous solution of the ingredients of the amino-aldehyde condensation product the dihydrogen phosphate of a base whose dihydrogen phosphate will separate from solution on removal of solvent before its monohydrogen phosphate, such as an alkali metal or ammonium dihydrogen phosphate, and also a salt of the selected metal, such as magnesium, with an acid which is stronger than phosphoric acid. It is, of course, desirable that neither the salt of the selected metal with such acid stronger than phosphoric acid nor the dihydrogen phosphate of the base should separate first from the solution on removal of solvent. An aqueous solution containing an acid salt of a selected metal with a polybasic acid, other than phosphoric acid, having a first dissociation constant in water of not less than 10' can be produced in analogous manner.

The present invention makes use of the fact which we have observed, that when there is introduced into an aqueous solution of the ingredients of an amino-aldehyde condensation product an acid salt of a polybasic acid and also a salt of a selected metal with an acid stronger than said polybasic acid, the relative proportions of the solution and of the said salts being such that the critical concentration of a less acid salt of the selected metal is exceeded, then such less acid salt will separate and the aqueous solution will become more acid.

By using an acid salt of a polybasic acid having a first dissociation constant in water of not less than 10'- and by using a selected metal whose less acid salt with such polybasic acid has a sufficiently low solubility in water to separate from solutions containing a substantial proportion of water, the pH of the resulting solution can be sufficiently low to cause the separation of waterinsoluble amino-aldehyde condensation product in a particulate form suitable for delustring textile materials.

It is known that if an amino-aldehyde condensation product in particulate form is produced in contact with fibres, yarns or fabrics, the particles are deposited thereon and adhere thereto producing the effect known as delustring. It is also known that if a condensation product of resinous character is produced within the fibres then useful effects are produced in textile fabrics so treated or textile fabrics made from the yarns or fibres so treated, these effects being in general improved dimensional stability, improved fastness of many dyestuffs and improved resistance to creasing. It

is possible to produce these latter effects in combina tion with delustring. It is also known that to produce effects which have good wash-fastness, a final heating at a low pH is desirable.

Textile material can be delustred in accordance with the present invention by two successive impregnations with solution, the second at least being an aqueous solution and either of which contains the ingredients of an amino-aldehyde condensation product. The textile material is preferably dried or partially dried between the impregnations. Two alternative procedures are possible. In one of these, the first solution contains an acid salt of a polybasic acid having a dissociation constant in water of not less than 10- such as an alkali metal or ammonium dihydrogen phosphate, and the second solution contains a salt of the selected metal, such as magnesium or lead, with an acid stronger than said polybasic acid; in the other alternative procedure, the first solution contains the salt of the selected metal and the second solution contains the acid salt. When the first solution contains the said acid salt, it is preferable that the ingredients of the amino-aldehyde condensation product be incorporated in the second solution; if, however, they are incorporated in the first solution, it is preferable that the acid salt be not an ammonium salt.

According to one form of the present invention therefore, there is provided a process of producing a delustre effect on textile material which comprises impregnating the material with a solution containing an acid salt of a polybasic acid having a dissociation constant in water of not less than 10-, preferably drying or partly drying the so impregnated material, and then impregnating the sotreated material with an aqueous solution containing a salt with an acid stronger than said polybasic acid of a metal of which a less acid salt with said polybasic acid will separate from an aqueous solution of its acid salt on removal of water, the amount of acid salt introduced into the material by the first impregnation and the concentration of the solution used for the last-mentioned impregnation being such that separation of such less acid salt takes place on such impregnation, either solution containing the ingredients of an amino-aldehyde condensation product. According to a modification of the invention the aqueous solution used for the second impregnation contains the acid salt of a polybasic acid having a dissociation constant in water of not less than 10- and the solution used for the first impregnation contains the metal salt of an acid stronger than said polybasic acid.

On drying the further impregnated material, the concentration of the aqueous solution within and between the fibres will be increased with further lowering of the pH. If the solution still contains some resin-forming ingredients after removal of the greater part of the water, a final heating at a temperature above C. will bring about formation of resinous condensation product of good fastness to washing and even at temperatures below 100 C. such resin formation frequently occurs. The amount of such ingredients will, however, be rather variable if the customary crystalloidal intermediate condensation products of, for example, urea and formaldehyde or melamine and formaldehyde are used. If, therefore, it is desired to form some resinous condensation product, for example, to improve the crease-resistance of the fabric, the solution may advantageously include methylol ethers derived from urea and formaldehyde or melamine and formaldehyde. The methylol ethers do not give particulate precipitates. Thus, the dimethyl ether of dimethylol urea may be used for this purpose.

The acid salt may be, for example, a sodium, potassium or ammonium salt, e.g. the dihydrogen phosphate.

The selected metal, of which the less acid salt, such as the monohydrogen phosphate, separates from aqueous solution before the acid salt, such as the dihydrogen phosphate, at concentrations above the critical concentration may be, for example, barium, calcium, strontium,

thorium, zinc, copper,manganese, cadmium, cerium, lead or the cation U0 The acid stronger than the said polybasic acid may be, for example, hydrochloric acid or sulphuric acid or nitric acid, provided that the resulting solution does not unduly attack the ingredients of the amino-aldehyde resin or the textile material.

It is preferred to use acid salts of a metal such as an alkali metal, most suitably acid salts of sodium; the acid salts of ammonium are preferably not used since these can give rise to some reaction with the aldehyde or intermediate condensation product in the solution.

The aqueous solution formed in the textile material upon the second impregnation comprises a system of salts which behaves, as regards pH change, as if it were simply a solution, evaporated beyond the critical concentration, of the acid salt of the selected metal,

A few systems which have been found useful are:

(a) Sodium dihydrogen phosphate and magnesium chloride (b) Sodium dihydrogen phosphate and magnesium sulphate (c) Sodium dihydrogen phosphate and calcium chloride (d) Sodium hydrogen malon-ate and barium chloride (e) Disodium hydrogen phosphate and lead nitrate (f) Disodium dihydrogen pyroph'osphate and lead nitrate (g) Disodium dihydrogen pyrophosphate and zinc sulphate (h) Potassium hydrogen phosphite and lead nitrate (i) Potassium hydrogen oxalate and lead nitrate (j) Potassium hydrogen oxalate and magnesium sulphate (k) Potassium hydrogen oxalate and calcium chloride (I) Potassium hydrogen oxalate and barium chloride (m) Potassium hydrogen oxalate and zinc sulphate (n) Sodium hydrogen maleate and lead nitrate (0) Sodium hydrogen malonate and lead nitrate (p) Sodium hydrogen tartrate and lead nitrate (q) Sodium hydrogen tartrate and zinc sulphate (r) Potassium hydrogen phthalate and barium chloride (s) Sodium dihydrogen phosphate and lead nitrate (t) Sodium dihydrogen phosphate and barium chloride The acid salt of said polybasic acid and the salt of a selected metal with an acid stronger than said polybasic acid may be used in substantially equivalent proportions, although an excess of one or the other up to about 3 to 1 equivalents does not give rise to any inconvenience.

The ingredients of amino-aldehyde condensation products used in the solutions of the present invention may have as their amino component urea or melamine, for example, and as their aldehyde component formaldehyde or paraformaldehyde, for example. As already stated, the term ingredients includes partial condensates and we may therefore use in the solutions the water-soluble methylol compounds obtained by the condensation of urea or melamine with formaldehyde under alkaline conditions.

It is preferred to employ solutions which do not con-. tain ammonium ions or ions of organic bases. Accordingly, it is (as already stated) preferred that the acid salt (such as the dihydrogen phosphate) employed be an alkali metal acid salt, especially an acid salt of sodium. It is generally most convenient to employ the ingredients of the amino-aldehyde condensation product in the form of a water-soluble .crystalloidal intermediate condensation product produced in known manner under neutral or alkaline conditions. It is preferred to employ such an intermediate condensation product for the preparation of the solutions of the present invention but it is preferred also to use one whose formation has not been catalysed by means of ammonia.

When the aqueous solution used for the second impregnation contains the ingredients of the amino-aldehyde resin, care must be taken to ensure that its pH is not unduly lowered by salt which may be extracted from the textile material during the second impregnation. The risk of this is particularly great where the less acid salt has a very 'low critical concentration, e.g. lead monohydrogen phosphate. This risk can be minimised by including in either of the solutions a buffer. If the intermediate condensation product is one which has been made with the aid of alkali this will serve as the buffer. The effect of buffering is discussed in the aforesaid application Serial No. 581,508, April 30, 1956.

The process of the presentinvention possesses a number of advantages over the process hitherto employed using solutions which depended for the development of acidity upon decomposition of an ammonium salt. The development of acidity by reaction of ammonium salts With aldehyde or intermediate condensation product gives rise to the production of volatile bases which are liable to have an unpleasant odour. Such volatile bases are not produced from those solutions employed in the process of the present invention which do not contain ammonia or an ammonium salt. The use of ammonia and/or ammonium salts in the solutions causes the production of hexamine which adversely affects light-fastness of certain direct dyestuffs. Hexamine is not produced with those solutions employed in the process of the present invention which do not contain ammonia or an ammonium salt. Solutions in which the development of acidity is caused by the reaction of ammonium salts are dependent for their effect upon the free formaldehyde content of the solutions. The development of acidity in the solutions employed in the process of the present invention which do not con tain ammonium salt is independent of the free formalde/ hyde content of the solutions. Even if there are employed in the process of the present invention solutions which do contain ammonium salts, these undergo a development of acidity which is independent of any acidity produced by the reaction of the ammonium salt with free formaldehyde in the solutions.

One advantage of the process of the present invention, is that the delustring effect and the quantity of particulate precipitate which is formed can be more easily controlled than in the known process. Another advantage is that it is more easy, with the process of the present invention, to combine the delustring with improvement in the properties of the textile materials, such as improved resistance to creasing, consequent upon the formation of resinous condensation product within the fibres. Moreover, the present invention does not involve the use of strong acids whose detrimental effects on textile materials are well known.

It has been found that when textile materials are delustred by the process of the present invention, some of the salt of the selected metal which Was precipitated is associated with the condensation product whose particles are deposited on the textile material. If the textile material istreated with a sequestering agent, as may happen in laundering, the selected metal can be removed and this removal may be accompanied by removal of some or all of the particulate condensation product.

This disadvantage can be reduced by using a selected metal which is not removed by sequestering agents likely to be applied to the textile material. Thus calcium salts are less suitable than barium salts since calcium is more efiectively sequestered than barium by sodium hexametaphosphate, a compound which is contained in certain commercial detergent preparations. The disadvantage can also be minimised or even avoided by ensuring that the solution contained in the fabric, after deposition of the condensation product in particulate form, still contains resin-forming ingredients and by heating the textile material after drying to a sufiiciently high temperature to form resinous condensation product from such ingredients. By doing this, there may also be conferred upon the fabric the known improvements in properties consequent upon formation of synthetic resin therein, such as improved resistance to creasing.

It is possible to produce delustred patterns on a lustrous background or lustrous patterns on a delustred background in carrying out the process of the present inven- Example J.Production of lustrous prints on delustred ground A piece of 10 shaft end satin having a filament viscose rayon warp and spun viscose rayon weft was printed with a printing paste of the following composition,

20% British gum D26 8% trisodium phosphate 2.5 formosul 5% urea 3% glycerol 5% colour (Caledon Jade Green XN 200) Bulk to 100 ccs. with water After printing the fabric was dried and then steamed for 5 mins. at 100 C. in an ager and dried. The fabric was impregnated through an aqueous solution containing 9% sodium dihydrogen phosphate and nipped off through a mangle having a water expression of 85%. After drying the fabric was impregnated through an aqueous solution containing 10% lead nitrate and 19% solids content of urea-formaldehyde precondensate of ratio 1.6 molecules of formaldehyde per molecule of urea. The fabric was then nipped off through a mangle having a water expression of 85% and dried. After drying the fabric was baked at 140 C. for 3 mins. and then immersed in 0.2% sodium perborate solution at 20 C. for 20 mins, to re-oxidise the dyestufi' in the printed areas, washed and immersed for mins. in 4% hydrochloric acid at C. to ensure complete relustring of the printed areas. The fabric was then washed and boiled for 1% hrs. in an aqueous solution of soap, 4% soda ash to remove loose colour and delustrant and subsequently washed in hot water followed by cold water. After drying up, the fabric was seen to have lustrous coloured printed areas on a delustred ground and possessed good crease-resistance on both the lustrous and delustred areas.

Example 2.Proa'uction of delustred prints on delustred ground A piece of viscose satin as used in Example 1 was printed with a printing paste having the following composition:

) After printing the fabric was dried and steamed for 5 mins. at 100 C., dried and padded through an aqueous solution containing 8% sodium dihydrogen phosphate, nipped off through a mangle having a water expression of 110% and again dried. The fabric was then impregnated through an aqueous solution containing 7% lead nitrate and 16% solids content of urea-formaldehyde precondensate of ratio 1.6 molecules of formaldehyde per molecule of urea, nipped off through a mangle having a water expression of 110% and dried. The fabric was then baked for 3 mins. at 140 C. After baking the fabric was immersed in 0.2% sodium perborate solution for 20 mins. at 20 C. to oxidise the dyestutf in the printed areas, washed and boiled for 1% hrs. in an aqueous solution containing soap, soda ash to remove loose colour and loose delustrant and subsequently washed in hot water followed by cold water; After drying the fabric possessed delustred coloured printed areas on a delustred ground and had a good crease-resistance on both the printed and non-printed areas.

Example 3.--Production of lustrous and delustred prints on delustred ground A piece of viscose satin as described in Example 1 was printed in certain areas with a printing paste of the following composition.

Paste A:

25% British gum D26 30% trisodium phosphate 2.5% formosul 5% urea 3% glycerol I 5% colour (Caledon Jade Green XN 200) Bulk to ccs. with water This paste was prepared by making a 50% solution of British gum D26 and adjusting it to the correct alkali content by adding slowly a hot solution of gms. trisodium phosphate in 100 ccs. water.

In certain other areas the prints were done with a printing paste of the following composition.

Paste B:

20% British gum D26 2.5% formosul 5% urea 3% glycerol 5% colour (Caledon Jade Green XN 200) Bulk to 100 ccs. with water After printing the fabric was dried, steamed for 5 mins. at 100 C. and then dried.

The fabric was padded through a solution containing 6% sodium dihydrogen phosphate, nipped off through a mangle having a Water expression of and dried. After drying the fabric was impregnated through a solution containing 16% solids content of urea-formaldehyde precondensate of ratio 1.6 formaldehyde molecules to one molecule of urea and 7% of lead nitrate, nipped off, through a mangle having a water expression of 110% and dried. After drying the fabric was baked for 3 mins. at C. and immersed in 0.2% sodium perborate solution for 20 mins. at 20 C. to re-oxidise the dyestuff in the printed areas, washed and immersed for 15 mins. in hydrochloric acid at 20 C. to ensure complete relustring of the areas printed with paste A and rewashed. It was boiled for 1% hrs. in an aqueous solution of 4% soap, soda ash to remove loose colour and loose delustrant and subsequently washed in hot water followed by cold water. After drying the fabric was seen to possess lustrous printed areas which had been printed with paste A and delustred printed areas where the fabric had been printed with paste B, and to be well delustred on the non-printed areas. All parts of the fabric were found to possess good crease-resistance.

Example 4.Pr0duction of delustred print on lustrous ground A piece of viscose satin as described in Example 1 was printed with a paste of the following composition:

Thickener:

50 gms. gum tragacanth (3%) 8 gms. wheat starch 42 ccs. water Paste:

100 gms. thickener 3 ccs. 33% sodium hydroxide solution 3 ccs. wetting agent sold under the trade name Alcopol O 5 gms. colour (Rapidogen Colour Bordeaux Red) 20 gms. CaCl in 70 ccs. water and then dried. The fabric was padded through a twobowl mangle, the lower bowl being wrapped with a woollen fabric and the bottom half of said bowl being arranged to dip into a trough containing an aqueous solution of 15% ammonium dihydrogen phosphate and 16% solids content of urea-formaldehyde precondensate of ratio 1.6 molecules of formaldehyde to 1 molecule of urea. The dyestuff was then fixed by passing immediately through an oven containing steam at 95 C. and dried. When dry the fabric was boiled in soap, soda ash solution for 1 hr. to remove loose colour and subsequently washed in hot water followed by cold water. After drying the fabric was found to be crease-resisting and possessed delustred coloured printed areas on lustrous grounds.

Example 5 .All-over delustre without curing A piece of viscose satin as described in Example 1 was impregnated twice through a solution of 8% sodium dihydrogen phosphate, nipped off through a mangle having a water expression of 85% and dried. The fabric was then impregnated through a solution containing 19% solids content of urea-formaldehyde precondensate of ratio 1.6 molecules of formaldehyde per molecule of urea, 9% lead nitrate and 1% Lissapol N, nipped off through a mangle having a water expression of 85% and dried. The fabric was then washed in an aqueous solution of soap, A% soda ash for 2 mins. at 90 C., and after washing free of soap and soda ash, was dried. The resulting fabric possessed a matt delustred appearance and good crease-resistance.

We claim:

1. A process for producing a delustre efl ect on a textile material which comprises depositing on the fibres of the textile material an amino-aldehyde condensation product in particulate form derived from a catalytic reaction between two liquors with which the textile material is successively impregnated, the second at least of which liquors is an aqueous liquor, one of said liquors containing, in solution, at least one acid salt of a polybasic acid having a first dissociation constant in water greater than 10- selected from the group consisting of the alkali metal acid salts and the ammonium acid salts of said polybasic acid, and the other of said liquors containing, in solution, a metal salt of an acid stronger than said polybasic acid, the metal of said metal salt being one of which a less acid salt with said polybasic acid will separate out, on removal of water from an aqueous solution containing, in solution, said acid salt of said polybasic acid and said metal salt of said acid stronger than said polybasic acid, before the acid salt of said metal with said polybasic acid, the concentration of said acid salt of said polybasic acid and of said metal salt of an acid stronger than said polybasic acid in the respective liquors being such that said less acid salt separates from its aqueous solution as soon as said textile material is impregnated with the second of said liquors.

2. A process as claimed in claim 1 in which the metal salt with an acid stronger than said polybasic acid is a salt of a metal selected from the group consisting of barium, calcium, strontium, magnesium, lithium, zinc, copper, manganese, cadmium, lead and the cation U0 3. A process for producing a delustre effect on a textile material which comprises depositing on the fibres of the textile material an amino-aldehyde condensation product in particulate form derived from a catalytic reaction between two aqueous liquors with which the textile material is successively impregnated, one of said aqueous liquors containing, in solution, at least one dihydrogen salt of orthophosphoric acid selected from the group consisting of the alkali metal dihydrogen orthophosphates and ammonium dihydrogen orthophosphate, and the other of said aqueous liquors containing, in solution, a metal salt of an acid stronger than orthophosphoric acid, the metal of said metal salt being one whose monohydrogen orthophosphate will separate out, on removal of water from an aqueous solution containing, in solution, said dihydrogen salt of orthophosphoric acid, together with said salt of said acid stronger than orthophosphoric acid, before the dihydrogen orthophos phate of said metal, the concentration of said dihydrogen salt of orthophosphoric acid and of said metal salt of an acid stronger than orthophosphoric acid in the respective aqueous liquors being such that said monohydrogen phosphate separates from its aqueous solution as soon as said textile material is impregnated with the second of said aqueous liquors.

4. A process as claimed in claim 3 in which the metal salt with an acid stronger than orthophosphoric acid is lead nitrate.

5. A process as claimed in claim 3 in which the metal salt with an acid stronger than orthophosphoric acid is magnesium chloride.

References Cited in the file of this patent UNITED STATES PATENTS 2,152,182 Ellis Mar. 28, 1939 2,217,114 Hefti Oct. 8, 1940 2,305,006 Holt Dec. 15, 1942 2,416,988 Foulds Mar. 4, 1947 2,424,284 O1pin July 22, 1947 2,484,481 Arthur Oct. 11, 1949 2,653,921 Sulzer Sept. 29, 1953 2,684,346 Nickerson July 20, 1954 2,762,719 Kleiner Sept. 11, 1956 2,930,106 Wrotnowski Mar. 29, 1960 

1. A PROCESS FOR PRODUCING A DELUSTRE EFFECT ON A TEXTILE MATERIAL WHICH COMPRISES DEPOSITING ON THE FIBRES OF THE TEXTILE MATERIAL AN AMINO-ALDEHYDE CONDENSATION PRODUCT IN PARTICULATE FORM DERIVED FROM A CATALYTIC REACTION BETWEEN TWO LIQUORS WITH WHICH THE TEXTILE MATERIAL IS SUCCESSIVELY INPREGNATED, THE SECOND AT LEAST OF WHICH LIQUORS IS AN AQUEOUS LIQUOR, ONE OF SAID LIQUORS CONTAINING, IN SOLUTION, AT LEAST ONE ACID SALT OF A POLYBASIC ACID HAVING A FIRST DISSOCIATION CONSTANT IN WATER GREATER THAN 10**-6 SELECTED FROM THE GROUP CONSISTING OF THE ALKALI METAL ACID SALTS AND THE AMMONIUM ACID SALTS OF SAID POLYBASIC ACID, AND THE OTHER OF SAID LIQUORS CONTAINING, IN SOLUTION A METAL SALT OF AN ACID STRONGER THAN SAID POLYBASIC ACID, THE METAL OF SAID METAL SALT BEING ONE OF WHICH A LESS ACID SALT WITH SAID POLYBASIC ACID WILL SEPARATE OUT, ON REMOVAL OF WATER FROM AN AQUEOUS SOLUTION CONTAINING, IN SOLUTION, SAID ACID SALT OF SAID POLYBASIC ACID AND SAID METAL SALT OF SAID ACID STRONGER THAN SAID POLYBASIC ACID, BEFFOR THE THE ACID SALT OF SAID METAL WITH SAID POLYBASIC ACID, THE CONCENTRATION OF SAID ACID STRONGER THAN SAID POLYBASIC ACID IN THE SALT OF AN ACID STRONGER THAN SAID POLYBASIC ACID IN THE RESPECTIVE LIQUORS BEING SUCH THAT SAID LESS ACID SALT SEPARATES FROM ITS AQUEOUS SOLUTION AS SOON AS SAID TEXTILE MATERIAL IS IMPREGNATED WITH THE SECOND OF SAID LIQUORS. 